It was the end of the war and Vancouver was in the mood to party when in all the revelry U.S. Navy serviceman Sam Tridente had his Dixie-cup sailor's hat swiped off his head by an exuberant little souvenir-seeker.

"He was stationed in Vancouver, and during VJ day after Japan surrendered, there were wild celebrations in the city of Vancouver," said grandson Mike Tridente.

"And apparently a little boy ran up to him, took his hat as a souvenir and this is something he's regretted for 70 years now."

Now the younger Tridente has launched an international search for the traditional Dixie-cup style hat with "S-Tridente" written inside.

"It's from the early 40s so I'm sure if it's still around it's not in the best condition but I think that adds to the whole appeal of it," said Tridente.

Tridente knows finding it is an incredible long shot, but it would be the gift of a lifetime for Sam, who turns 90 in May.

If you think you know where the hat might be you can send a message to Finding Sam's Hat on Facebook.

With files from the CBC's Tim Weekes